Ceramic mixture paste, porous body, electrostatic chuck, and substrate fixing device

Abstract

A ceramic mixture paste includes oxide ceramic particles, burn-off particles, and a firing aid. The burn-off particles are burned off at a temperature lower than the firing temperature of the oxide ceramic particles. The firing aid melts at a temperature lower than the firing temperature. The ratio of the volume of the burn-off particles to the volume of the oxide ceramic particles is more than 0% and less than or equal to 20%.

What is claimed is: 
     
       1. A ceramic mixture paste comprising:
 oxide ceramic particles; 
 burn-off particles that are burned off at a temperature lower than a firing temperature of the oxide ceramic particles; and 
 a firing aid that melts at a temperature lower than the firing temperature, 
 wherein the oxide ceramic particles, the burn-off particles, and the firing aid are mixed in paste form, and 
 a ratio of a volume of the burn-off particles to a volume of the oxide ceramic particles is more than 0% and less than or equal to 20%. 
 
     
     
       2. The ceramic mixture paste as claimed in  claim 1 , wherein an average particle size of the burn-off particles is greater than an average particle size of the oxide ceramic particles. 
     
     
       3. The ceramic mixture paste as claimed in  claim 1 , wherein
 the oxide ceramic particles are aluminum oxide particles, and 
 the burn-off particles are polymethyl methacrylate particles. 
 
     
     
       4. A porous body comprising:
 oxide ceramic particles; and 
 a firing aid binding the oxide ceramic particles, 
 wherein a porosity of the porous body is more than 30% and less than or equal to 43%. 
 
     
     
       5. An electrostatic chuck comprising:
 a base including a through hole, the base being configured to attract and hold a substrate; and 
 a porous body in the through hole, the porous body including spherical oxide ceramic particles as a principal component, the porous body including pores that form a gas passage, the porous body having a porosity of more than 30% and less than or equal to 43%, 
 wherein an average size of the pores is greater than an average size of the spherical oxide ceramic particles. 
 
     
     
       6. A substrate fixing device comprising:
 a baseplate; and 
 the electrostatic chuck as set forth in  claim 5 , the electrostatic chuck being on the baseplate.